OLIVER Yates, the new chief executive of the government's Clean Energy Finance Corp, may not have an office yet but he is already receiving informal proposals for his green bank's $10 billion in funds.

''There are a lot of people who are keen to see the CEFC up and running, and are putting proposals forward in potential areas where we could participate and help them,'' the former Macquarie banker said.

Now in his second week at the helm, Mr Yates will use the next few months to find more permanent digs and build a team that can start selecting recipients of the bank's first loan tranche of $2 billion for the year beginning next July.

The CEFC's mandate is to operate at no cost to the taxpayer by generating a return matching or exceeding the government's yearly cost of funds of about 3.5 per cent. ''We have a clear obligation here to act commercially,'' he said. ''There's no free money in this game.''

Its funds, which fall outside the federal budget, are earmarked to support renewable energy technologies and projects that are near-commercial but are unable to secure longer-term private finance.

The global financial crisis ''has caused issues for funding at long duration'', Mr Yates said. While banks are willing to back renewable energy projects with which they are familiar, such as some wind farms, less-established technologies such as tidal, wave and some forms of solar energy miss out.

While renewable energy may receive about half the CEFC's finance, energy efficiency efforts are likely to get most of the remainder.

''It's the cheapest thing for people to do,'' Mr Yates said. One example was the trouble local councils had switching to less energy-sapping street lighting. Councils paid the bills but often did not control the lights, he said.

Geoff Ward, chief executive of Geodynamics, a company seeking to tap geothermal power from hot rocks kilometres below the surface in South Australia's Cooper Basin, said the CEFC would be a ''motivated lender'' in providing funds and encouraging others to invest in renewable energy.

Mr Ward said his company, which has won $90 million in government grants, would expect to meet tough demands if it ever sought CEFC finance. ''We've got to demonstrate that we have a project that's been appropriately investigated and appraised, with the risk management metrics and approaches you'd expect for any large resource and power development,'' he said.

The opposition, however, has dubbed the CEFC ''a giant slush fund'' and vowed to scrap it along with the carbon tax.

''By its very nature [the fund] will be high-risk, irrespective of what systems are put in place,'' said Greg Hunt, the opposition's environment spokesman. ''If the risk was low, they would be able to attract private finance.''

Mr Hunt said the CEFC was basically flawed: ''The Renewable Energy Target is already operating as a market mechanism to encourage investment in renewables and that should be allowed to operate without another $10 billion distorting that scheme.''

Mr Yates, though, hopes critics relent when they see the fund in action. ''I'm not expecting to go anywhere, and I'm not expecting anything to happen except for us to become an integral part of the industry.''